Apparatus for controlling the supply of ink and dampening fluid in an offset printing machine

ABSTRACT

The rate of ink supply in an offset printing machine having an ink fountain roller operated by a pawl and ratchet is controlled by a deflector cam acting on the pawl to vary its effective stroke, and by a manually operated control disc which adjusts the position of the cam. A transfer roller in the roller train of the dampening mechanism is rocked toward and away from simultaneous engagement with a water fountain roller and a distributing roller, and its dwell time in the engaged position is controlled by an adjustable linkage manually set by another control disc. A control bar simultaneously stops the ink and water supplies by interrupting the drive train of the pawl and by keeping the transfer roller out of the engaged position.

United States Patent Inventors Heinz Joachim Schinke Unterkirnach; Hermann Raihle, St. Georgen, Germany Appl. No. 721,861 Filed Apr. 16, 1968 Patented Jan. 5, 1971 Assignee Math Bauerle GmbIl St. Georgen, Germany Priority Apr. 17, 1967 Germany No. B92102 APPARATUS FOR CONTROLLING THE SUPPLY OF INK AND DAMPENING FLUID IN AN OFFSET PRINTING MACHINE 6 Claims, 2 Drawing Figs.

US. Cl 101/148, 101/352,101/363 Int. Cl B41f3l/12, B411 25/02 Field ofSearch 10l/363,

References Cited UNITED STATES PATENTS 2,065,535 12/1936 Morse 101/148 2,857,840 10/1958 Bachman.. 101/148 3,279,371 10/1966 Mestre 101/352 Primary Examiner-William B. Penn Assistant Examiner-E. M. Coven Attorney-Kelman and Berman ABSTRACT: The rate of ink supply in an offset printing machine having an ink fountain roller operated by a pawl and ratchet is controlled by a deflector cam acting on the pawl to vary its effective stroke, and by a manually operated control disc which adjusts the position of the cam. A transfer roller in the roller train of the dampening mechanism is rocked toward and away from simultaneous engagement with a water fountain roller and a distributing roller, and its dwell time in the engaged position is controlled by an adjustable linkage manually set by another control disc. A control bar simultaneously stops the ink and water supplies by interrupting the drive train of the pawl and by keeping the transfer roller out of the engaged position.

PATENTEU JAN 5 l97| SHUT 1 OF 2 PATENTH] JAN 519m SNEH 2 OF 2 mvmRs Heinz Jam/1 im SchLnKa BY Her/mm Hm! WWII/L1. I Mal/M BACKGROUND OF THE INVENTION This invention relates to offset printing machines, and particularly to apparatus for'controlling the su ply of ink and dampening fluid to a master on the plate cylinder of an offset printing machine.

The invention is more specifically concerned with small offset printing machines for use in offices by personnel unskilled in the printing trade. It is conventional in printing shops to adjust the supply rate of ink and dampening fluid by trial and error on the basis of proof sheets. An experienced printer quickly establishes proper supply rates on the basis of one or two trial runs. Clerical help operating an office-type offset machine normally lacks the skill necessary for making supply adjustments within a reasonable time andat reasonable cost.

An object of the invention is the provision of controls for the ink and dampening fluid supply of a small offset printing machine which are simple and give reproducible results so that the machine may be equipped by its manufacturer with tables indicating the settings for ink and dampening fluid controls which produce acceptable prints under various conditions, such as the nature of the master employed, the characteristics of the printed image, and the like.

SUMMARY OF THE INVENTION In its basic aspects, the invention provides an offset printing machine of the type described with three controls. The first control stops and starts the transfer of ink and dampening fluid from respective fountains to the plate cylinder of the machine while the machine drive operates. The second control varies the rate of ink transfer independently from the rate of dampening fluid transfer, that is, even at a constant rate of dampening fluid transfer. The third control permits the dampening fluid to be transferred at varying rates from the dampening fluid fountain to the plate cylinder even when the ink supply is constant.

The train of engageable rollers which is interposed between one of the fountains and the plate cylinder may include one roller which is driven by a ratchet and a pawl oscillated by the main drive of the machine. The overall rate of rotation of theroller is varied by a settable control member, a deflecting arrangement associated with the pawl varying the engagement of the pawl with the ratchet in response to the setting of the control member.

The train of rollers between the other fountain and the plate cylinder includes two spacedly arranged rollers and a third roller which is moved by the main machine drive toward and away from a position of simultaneous engagement with the two spaced rollers. The dwell time of 'the third roller in that position is varied by one of the aforementioned second and third controls.

Other features, additional objects and many of the attendant advantages of this invention willireadily be appreciated as the same becomes better understood by reference to the following detailed description of a preferred embodiment when considered in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a fragmentary side-elevational, sectional view of an offset printing machine of the invention; and

FIG. 2 shows the machine of FIG. 1 in fragmentary section in a different plane parallel to that of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing in'de'tail, and initially to FIG. 1, there is seen as much of the inking mechanism F of an offset printing machine as is needed for an understanding of the invention.

Ink S is held in a fountain partly illustrated in FIG. 1 by a fountain blade 1 and a fountain roller 2. A control disc 3 is rotatably mounted on a fixed shaft 4 which is an element of the supporting frame of the machine, now shown in detail. The angular position of the disc 3 on the shaft 4 is indicated by the relative position of circumferentially spaced. differently colored indicia 5a, 5b, 50 on the disc 3 and an index mark 6 fixed on the stationary machine structure.

A gear 7 coaxially attached to the control disc 3 meshes with a gear segment 8 on a radial cam disc 9, the disc 9 and the fountain roller 2 being rotatably supported on a common fixed shaft 10. In the illustrated position of the cam disc 9, which acts as a deflector, a notch 11 in the circumference of the disc 9 is angularly offset from a pawl 12. When the pawl enters the notch 11, it engages the teeth of a ratchet 13 fixedly mounted on the ink fountain roller 2.

The pawl 12 is mounted on a pawl carrier 14 which is rotatably supported on the shaft 10 and is provided with a partial, circumferential gear rim 15. A shaft 16 joumaled in the machine frame carries a fixed arm 17. A toothed end face of the arm 17 meshingly engages the gear rim 15 of the pawl carrier 14. A cam follower roller 18 on the arm 17 is swung back and forth about the axis of the shaft 16, as indicated by a double arrow, by an eccentric cam 19 on a drive shaft 26 when the arm 17 is in the illustrated position. The shaft 26 is coupled to the nonillustrated electric drive motor of the printing machine in a conventional 'manner and rotates continuously as long as the motor is energized. It is thus a portion of the machine drive which also turns the plate, blanket and impression cylinders of the machine which maybe conventional and are not seen in the drawing.

A shifting lever 25 fixedly mounted on the shaft 16 and thereby coupled to the arm 17 is biased clockwise relative to the axis of the shaft 16, as seen in FIG. 1, by a helical tension spring 20 interposed between one arm of the lever 25 and the machine frame. The spring 20 thus holds the cam follower roller 18 in contact with the cam 19. The other arm of the shifting lever 25 carries an axially projecting pin 24.

A cam plate 23 is pivotally mounted on the drive shaft 26, and is angularly shifted on the shaft by means of a control bar 21 which is moved back and forth during the operating cycle face 230 holds a detent 22 in the illustrated angular position v on a fixed shaft 27 against the restraint of a helical tension spring 28 which tends to pull the detent 22 into engagement with the pin 24 on the lever 25.

The inking mechanism shown in FIG. 1 is operated as follows:

As long as the cam plate 23 is held by the control bar 21 in the illustrated operative position, the arm 17 is swung back and forth by the cam 19, and thereby oscillates the pawl 12 from the illustrated position to the right, as indicated by an arrow, and back again. The weight of the pawl.l2 or a nonillustrated pawl spring causes the tip of the pawl to travel along the face of the deflector cam 9, and to index the fountain roller 2 clockwise by engagement with the teeth of the ratchet 13. The angular distance traveled by the roller 2 during each oscillation of the pawl 12 is determined by the angular position of the notch 11 relative to the shaft 10. The notch is positioned by the control disc 3, and alignment of the indicia 5a, 5b, 5c with the index mark 6 indicates whether the ink fountain roller 2 is indexed by one, two or three tooth spacings of the ratchet 13, the adjusted position of the disc 3 being secured by friction.

As is'conventional in this art, the roller train which conveys ink from the fountain blade 1 to a nonillustrated plate cylinder includes, in addition to the fountain roller 2, a rocking transfer roller of the type described hereinbelow with reference to FIG. 2 and enough intermediate rollers to convey the ink to a distributing roller shown in FIG. 2. The system of rollers which provide the distributing roller with ink and dampening fluid, hereinafter referred to as water," has been described in general in our copending application, Ser. No. 716,141, filed on Mar. 26, 1968, now US. Pat No. 3,517,613, for an Offset Printing Machine.

The rate at which ink is transferred from the fountain between the blade 1 and the roller 2 to the distributing roller and the plate cylinder is directly related to the overall or average rate at'which the roller 2 is rotated by the pawl 12, and thus to the position of the ink control disc 3.

When the camrplate 23 is swung counterclockwise on the shaft 26 in such a manner that the detent 22 can be moved counterclockwise, as viewed in FIG. 1, by the spring 28, the pin 24 drops behind a shoulder 29 on the detent. The arm 17 thereafter is out of the effective range of the cam 19. it is moved by the rotating cam 19 through an angle too small to bring the pawl 12 into effective engagement with the ratchet 13. The bar 21 thus causes the rotary movement of the fountain roller 2 to stop and start, and the disc 3 controls the overall or average rotary speed of the roller 2.

The dampening mechanism W of the printing machine has 1 several elements in common with the apparatus shown in FIG.

1, as will becomeapparent from .the following description of FIG. 2.

The dampening mechanism includes a rocking transfer roller 30 permanentlyengaged with a fountain roller 31 which dips into-.a water tray as more fully described in our last-mentioned copending application, and intermittently engaged with a distributing roller 32 to which ink is conveyed by the mechanism partly illustrated in FIG. .1. lnk and Water are .furthertransferred to a nonillustrated plate cylinder.

The rate at which water is drawn from the nonillustrated tray is controlled by a water control disc 33 closely similar to the aforedescribed ink control disc 3 and mounted below the ink control disc. The angular position of the water control disc 33 on its stationary shaft 34 is indicated by indicia a, 5b, 5c on the disc 33 and a stationary index mark 6. A radial end face of the disc 33 has a circumfe'rentially elongated cam groove 42 whose outer face is approximately circular about the axis of rotation of the disc 33, and whose inner face is approximately spiral-shaped relative to that axis.

One arm of a lever 36 which turns on a fixed pivot carries a cam follower pin 35 received in the groove 42 and held against the spiraling inner face by a nonillustrated spring. The other arm of the lever 36 carries a locking roller 39 which is inoperative in the position of the device-shown in F IG. 2. An approximately triangularrocker 37 is pivoted to the lever 36 by a pivot pin 43 in one corner of the rocker. A cam follower roller 38 is mounted in another corner by means of a shaft 44 and is held in engagement with the eccentric radial cam 19 on the drive shaft 26 by a nonillustrated spring.

A pair oflinks 40, of which only one is seen in FIG. 2, is hingedly fastened to the third corner of the rocker 37 and carries the aforementioned rocking transfer roller 30. A helical tension spring 41 holds the roller 30 in permanent engagement I with the water fountain roller 31.

In the illustrated position of the cam plate 23, the dampening mechanism operatesas follows:

When the shaft 26 rotates, the rocker 37 is swung back and forth on the pivot pin 43 by the cam 19 and the cam follower roller 38, as indicated by a curved double arrow. When the end of the link 40 attached to the rocker 37 moves upward from the illustrated position, the other end of the link is moved downward and toward the left by the spring 41 as the transfer roller 30 moves along the surface of the fountain roller 31 and ultimately engages the distributing roller 32, thereby stopping the cam follower roller 38. During continuing rotation of the roller 32 depends on the location of. the pivot pin 43 from which the rocker 37 is suspended,-and therefore on the angular position of the watercontrol 'disc 33. 1f the disc 33 is moved counterclockwise from the illustrated position, 'the rocker 37 is also moved counterclockwiseand the links 40 are shifted to the right, thereby shorteningthe time of engagement of the transfer roller30 with th'e' distributing'roller 32, and reducing the rate of water transfer fron tlt lie nonillustrated tray to the nonillustrated plate cylinder by: the dampening mechanism W. r

When the control bar 21 swings the cam plate 23 counterclockwise from the illustrated position, the cam face 23b rides over the locking roller 39 and swings the lever 36 counterclockwise, whereby the pin35 is shifted toward the outer, circularly arcuate face of the cam groove'42. The resulting shift in the position of the pivot pin 43 away from.the..d istributing roller 32 keeps the transfer roller 30 out of-engagement with the distributing roller 32 in all angular positions ofthe garn l9.

The control bar 21 thus simultaneously starts and stops the transfer of ink and dampening fluid to the distributing roller, and thence to the plate cylinder, and the water control disc 33 controls the rate of water transfer as the ink control disc 3 controls the ink transfer.

While variously colored dots have been shown as indicia on the discs 3, 33, other indicia may be used to indicate the rate of ink or water transfer for which the machine is adjusted. A transfer-rate established for a given set of conditions, such as the nature of the master on the plate cylinder, can be reproduced at any future time by setting the index marks 6,6 to the proper indicia. The machine is normally equipped with a table of optimal settings for the discsl3, 33 under the conditions usually encountered in office reproduction work, and

satisfactory prints can be produced without further trial and,

error by entirely inexperienced personnel following the table. It should be understood, of course that-the foregoing disclosure relates only to preferred embodiments of the invention, and that it is intended to cover all changes and modifications of the example of the invention herein. chosen for the purpose of the disclosure which do not constitute departures from the spirit and scope of the invention set forth in the aping a train of engageable rollers rotatable about respective axes and adapted to be interposed between one of said fountain means and said plate cylinder, and rotatable drive means for operating said transfer means, the improvement which comprises:

a. first control means for stopping and starting operation of said transfer means while said drive means rotate;

b. second control means for varying the rate of ink transfer from said ink fountain means to said plate cylinder while the rate of water transfer is constant;

c. third control means for varying the rate of water transfer from said water fountain means to said plate cylinder while the rate of ink transfer ,is constant, one of said second and third control means being associated with said one fountain means;

d. a ratchet coaxially mounted on one of said rollers;

e. a pawl carrier angularly movable about the axis of said one roller; 1 1

f. a pawl mounted on said pawl carrier and engageable with said ratchet;

I. said drive means including a first cam member, means for rotating said cam member, and cam follower means in motion transmitting engagement with said pawl carrier for oscillating said pawl about the axis of said one roller when said cam follower means engages said cam member,

2. said first control means including shifting means for shifting said cam follower means into and out of effective engagement with said cam member,

3. said one control means including a manually settable control member angularly movable about an axis, and deflecting means responsive to the setting of said control member for varying the engagement of said pawl with said ratchet during said oscillating of said pawl and for thereby varying the overall rate of rotation of said one roller about the axis thereof,

4. said deflecting means including a second cam member angularly displaceable about the axis of said one roller and cammingly engaging said pawl during the oscillating thereof, and motion transmitting means connecting said control member and said second cam member for joint angular movement.

2. In a machine as set forth in claim .1, said shifting means including a shifting member connected to said cam follower means for joint movement, and detent means engageable with said shifting member for arresting the same in a position in which said cam follower means is out of effective range of said first cam member.

3. In an offset printing machine having inkfountain means, water fountain means, transfer means operable for transferring ink and water to a plate cylinder of said machine from said fountain means respectively, said transfer means including a first, a second, and a third roller rotatable about respec tive axes and adapted to be interposed between one of said fountain means and said plate cylinder, said first and second rollers being spaced from each other, and rotatable drive means for operating said transfer means, said drive means including moving means for moving said third roller toward and away from a position of simultaneous engagement with said first and second rollers, the improvement which comprises:

a. first control means for stopping and starting operation of said transfer means while said drive means rotate, said first control means including means adjustable for preventing said third roller from reaching said position and for permitting the third roller to reach said position;

b. second control means for varying the rate of ink transfer from said ink fountain means to said plate cylinder while the rate of water transferis constant; I

c. third control means for varying the rate of water transfer from said water fountain means to said plate cylinder while the rate of ink transfer is constant,

1. one of said second and third control means being associated with said one fountain means and including means for varying the dwell time of said third roller in said position,

2. said moving means including a rotatable cam member, means for rotating said cam member, a pivot, a rocker mounted on said pivot, cam follower means on said rocker engageable with said cam member for oscillating said rocker about said pivot, motion transmitting means connecting said rocker to said third roller,

3. said first control means and said one control means including shifting means for shifting said pivot.

4. In a machine as set forth in claim 3, the shifting means of said one control means including cam means having an axis and a continuous cam face, respective portions of said cam face being near and remote from said axis, a cam follower engaging said cam face, manual means for turning said cam means about said axis, and motion transmitting means interposed between said cam follower and said pivot.

5. In a machine as set forth in claim 3, said transfer means further comprising another train of engageable rollers rotatable about respective axes and adapted to be interposed between the other fountain means and said plate cylinder, and the other one of said second and third control means including means for varying the overall rate of rotation of one roller in said other train.

6. In a machine as set forth in claim 5, said first roller being a water fountain roller normally immersed in said water, and said one roller of said other train being an ink fountain roller. 

1. In an offset printing machine having ink fountain means, water fountain means, transfer means operable for transferring ink and water to a plate cylinder of said machine from said fountain means respectively, said transfer means including a train of engageable rollers rotatable about respective axes and adapted to be interposed between one of said fountain means and said plate cylinder, and rotatable drive means for operating said transfer means, the improvement which comprises: a. first control means for stopping and starting operation of said transfer means while said drive means rotate; b. second control means for varying the rate of ink transfer from said ink fountain means to said plate cylinder while the rate of water transfer is constant; c. third control means for varying the rate of water transfer from said water fountain means to said plate cylinder while the rate of ink transfer is constant, one of said second and third control means being associated with said one fountain means; d. a ratchet coaxially mounted on one of said rollers; e. a pawl carrier angularly movable about the axis of said one roller; f. a pawl mounted on said pawl carrier and engageable with said ratchet;
 1. said drive means including a first cam member, means for rotating said cam member, and cam follower means in motion transmitting engagement with said pawl carrier for oscillating said pawl about the axis of said one roller when said cam follower means engages said cam member,
 2. said first control means including shifting means for shifting said cam follower means into and out of effective engagement with said cam member,
 3. said one control means including a manually settable control member angularly movable about an axis, and deflecting means responsive to the setting of said control member for varying the engagement of said pawl with said ratchet during said oscillating of said pawl and for thereby varying the overall rate of rotation of said one roller about the axis thereof,
 4. said deflecting means including a second cam member angularly displaceable about the axis of said one roller and cammingly engaging said pawl during the oscillating thereof, and motion transmitting means connecting said control member and said second cam member for joint angular movement.
 2. said first control means including shifting means for shifting said cam follower means into and out of effective engagement with said cam member,
 2. In a machine as set forth in claim 1, said shifting means including a shifting member connected to said cam follower means for joint movement, and detent means engageable with said shifting member for arresting the same in a position in which said cam follower means is out of effective range of said first cam member.
 2. said moving means including a rotatable cam member, means for rotating said cam member, a pivot, a rocker mounted on said pivot, cam follower means on said rocker engageable with said cam member for oscillating said rocker about said pivot, motion transmitting means connecting said rocker to said third roller,
 3. In an offset printing machine having ink fountain means, water fountain means, transfer means operable for transferring ink and water to a plate cylinder of said machine from said fountain means respectively, said transfer means including a first, a second, and a third roller rotatable about respective axes and adapted to be interposed between one of said fountain means and said plate cylinder, said first and second rollers being spaced from each other, and rotatable drive means for operating said transfer means, said drive means including moving means for moving said third roller toward and away from a position of simultaneous engagement with said first and second rollers, the improvement which comprises: a. first control means for stopping and starting operation of said transfer means while said drive means rotate, said first control means including means adjustable for preventing said third roller from reaching said position and for permitting the third roller to reach said position; b. second control means for varying the rate of ink transfer from said ink fountain means to said plate cylinder while the rate of water transfer is constant; c. third control means for varying the Rate of water transfer from said water fountain means to said plate cylinder while the rate of ink transfer is constant,
 3. said one control means including a manually settable control member angularly movable about an axis, and deflecting means responsive to the setting of said control member for varying the engagement of said pawl with said ratchet during said oscillating of said pawl and for thereby varying the overall rate of rotation of said one roller about the axis thereof,
 3. said first control means and said one control means including shifting means for shifting said pivot.
 4. said deflecting means including a second cam member angularly displaceable about the axis of said one roller and cammingly engaging said pawl during the oscillating thereof, and motion transmitting means connecting said control member and said second cam member for joint angular movement.
 4. In a machine as set forth in claim 3, the shifting means of said one control means including cam means having an axis and a continuous cam face, respective portions of said cam face being near and remote from said axis, a cam follower engaging said cam face, manual means for turning said cam means about said axis, and motion transmitting means interposed between said cam follower and said pivot.
 5. In a machine as set forth in claim 3, said transfer means further comprising another train of engageable rollers rotatable about respective axes and adapted to be interposed between the other fountain means and said plate cylinder, and the other one of said second and third control means including means for varying the overall rate of rotation of one roller in said other train.
 6. In a machine as set forth in claim 5, said first roller being a water fountain roller normally immersed in said water, and said one roller of said other train being an ink fountain roller. 